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78.3656997680664 57 WikiText2 |
22350 = 7 / 2 ) suppresses the superconductivity , which is induced by eliminating this local moment ( J = |
255.40744018554688 20 WikiText2 |
22351 0 in Eu3 + ) . |
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22352 = = = Chemical properties = = = |
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22353 Europium is the most reactive rare earth element . It rapidly oxidizes in air , so that bulk oxidation of a centimeter @-@ sized sample occurs within several days . Its reactivity with water is comparable to that of calcium , and the reaction is |
84.55875396728516 47 WikiText2 |
22354 2 Eu + 6 H2O → 2 Eu ( OH ) 3 + 3 H2 |
132.50021362304688 15 WikiText2 |
22355 Because of the high reactivity , samples of solid europium rarely have the shiny appearance of the fresh metal , even when coated with a protective layer of mineral oil . Europium ignites in air at 150 to 180 ° C to form europium ( III ) oxide : |
69.41376495361328 49 WikiText2 |
22356 4 Eu + 3 O2 → 2 Eu2O3 |
170.5344696044922 8 WikiText2 |
22357 Europium dissolves readily in dilute sulfuric acid to form pale pink solutions of the hydrated Eu ( III ) , which exist as a nonahydrate : |
189.5273895263672 26 WikiText2 |
22358 2 Eu + 3 H2SO4 + 18 H2O → 2 [ Eu ( H2O ) 9 ] 3 + + 3 SO2 − |
103.91668701171875 23 WikiText2 |
22359 4 + 3 H2 |
754.6316528320312 4 WikiText2 |
22360 = = = = Eu ( II ) vs. Eu ( III ) = = = = |
27.952983856201172 17 WikiText2 |
22361 Although usually trivalent , europium readily forms divalent compounds . This behavior is unusual to most lanthanides , which almost exclusively form compounds with an oxidation state of + 3 . The + 2 state has an electron configuration 4f7 because the half @-@ filled f @-@ shell gives more stability . The + 2 s... |
46.18248748779297 244 WikiText2 |
22362 = = = Isotopes = = = |
85.05850219726562 7 WikiText2 |
22363 Naturally occurring europium is composed of 2 isotopes , 151Eu and 153Eu , with 153Eu being the most abundant ( 52 @.@ 2 % natural abundance ) . While 153Eu is stable , 151Eu was recently found to be unstable to alpha decay with half @-@ life of 5 + 11 |
82.87394714355469 55 WikiText2 |
22364 − 3 × 1018 years , giving about 1 alpha decay per two minutes in every kilogram of natural europium . This value is in reasonable agreement with theoretical predictions . Besides the natural radioisotope 151Eu , 35 artificial radioisotopes have been characterized , the most stable being 150Eu with a half @-@ lif... |
23.088985443115234 188 WikiText2 |
22365 The primary decay mode for isotopes lighter than 153Eu is electron capture , and the primary mode for heavier isotopes is beta minus decay . The primary decay products before 153Eu are isotopes of samarium ( Sm ) and the primary products after are isotopes of gadolinium ( Gd ) . |
53.59762191772461 51 WikiText2 |
22366 = = = = Europium as a nuclear fission product = = = = |
49.7862548828125 14 WikiText2 |
22367 Europium is produced by nuclear fission , but the fission product yields of europium isotopes are low near the top of the mass range for fission products . |
44.4245719909668 28 WikiText2 |
22368 Like other lanthanides , many isotopes , especially isotopes with odd mass numbers and neutron @-@ poor isotopes like 152Eu , have high cross sections for neutron capture , often high enough to be neutron poisons . |
280.748779296875 39 WikiText2 |
22369 151Eu is the beta decay product of samarium @-@ 151 , but since this has a long decay half @-@ life and short mean time to neutron absorption , most 151Sm instead ends up as 152Sm . |
447.41864013671875 41 WikiText2 |
22370 152Eu ( half @-@ life 13 @.@ 516 years ) and 154Eu ( half @-@ life 8 @.@ 593 years ) cannot be beta decay products because 152Sm and 154Sm are non @-@ radioactive , but 154Eu is the only long @-@ lived " shielded " nuclide , other than 134Cs , to have a fission yield of more than 2 @.@ 5 parts per million fissio... |
63.04705047607422 117 WikiText2 |
22371 155Eu ( half @-@ life 4 @.@ 7612 years ) has a fission yield of 330 parts per million ( ppm ) for uranium @-@ 235 and thermal neutrons ; most of it is transmuted to non @-@ radioactive and nonabsorptive gadolinium @-@ 156 by the end of fuel burnup . |
155.51637268066406 61 WikiText2 |
22372 Overall , europium is overshadowed by caesium @-@ 137 and strontium @-@ 90 as a radiation hazard , and by samarium and others as a neutron poison . |
129.65353393554688 32 WikiText2 |
22373 = = = Occurrence = = = |
117.10769653320312 7 WikiText2 |
22374 Europium is not found in nature as a free element . Many minerals contain europium , with the most important sources being bastnäsite , monazite , xenotime and loparite . |
116.67144012451172 30 WikiText2 |
22375 Depletion or enrichment of europium in minerals relative to other rare earth elements is known as the europium anomaly . Europium is commonly included in trace element studies in geochemistry and petrology to understand the processes that form igneous rocks ( rocks that cooled from magma or lava ) . The nature o... |
39.14323043823242 68 WikiText2 |
22376 Divalent europium ( Eu2 + ) in small amounts is the activator of the bright blue fluorescence of some samples of the mineral fluorite ( CaF2 ) . The reduction from Eu3 + to Eu2 + is induced by irradiation with energetic particles . The most outstanding examples of this originated around Weardale and adjacent par... |
60.07756042480469 90 WikiText2 |
22377 = = Production = = |
919.78857421875 5 WikiText2 |
22378 Europium is associated with the other rare earth elements and is , therefore , mined together with them . Separation of the rare earth elements is a step in the later processing . Rare earth elements are found in the minerals bastnäsite , loparite , xenotime , and monazite in mineable quantities . The first two ... |
94.02681732177734 60 WikiText2 |
22379 4 ( Ln denotes a mixture of all the lanthanides except promethium ) , and the third is a fluorocarbonate LnCO3F . Monazite also contains thorium and yttrium , which complicates handling because thorium and its decay products are radioactive . For the extraction from the ore and the isolation of individual lantha... |
34.5999870300293 251 WikiText2 |
22380 A few large deposits produce or produced a significant amount of the world production . The Bayan Obo iron ore deposit contains significant amounts of bastnäsite and monazite and is , with an estimated 36 million tonnes of rare earth element oxides , the largest known deposit . The mining operations at the Bayan... |
42.98750686645508 189 WikiText2 |
22381 = = Compounds = = |
950.1218872070312 5 WikiText2 |
22382 Europium compounds tend to exist trivalent oxidation state under most conditions . Commonly these compounds feature Eu ( III ) bound by 6 – 9 oxygenic ligands , typically water . These compounds , the chlorides , sulfates , nitrates , are soluble in water or polar organic solvent . Lipophilic europium complexes ... |
146.48690795898438 67 WikiText2 |
22383 = = = Halides = = = |
220.2959442138672 7 WikiText2 |
22384 Europium metal reacts with all the halogens : |
561.8969116210938 8 WikiText2 |
22385 2 Eu + 3 X2 → 2 EuX3 ( X = F , Cl , Br , I ) |
176.0304718017578 19 WikiText2 |
22386 This route gives white europium ( III ) fluoride ( EuF3 ) , yellow europium ( III ) chloride ( EuCl3 ) , gray europium ( III ) bromide ( EuBr3 ) , and colorless europium ( III ) iodide ( EuI3 ) . Europium also forms the corresponding dihalides : yellow @-@ green europium ( II ) fluoride ( EuF2 ) , colorless euro... |
8.773553848266602 96 WikiText2 |
22387 = = = Chalcogenides and pnictides = = = |
212.11106872558594 9 WikiText2 |
22388 Europium forms stable compounds with all of the chalcogens , but the heavier chalcogens ( S , Se , and Te ) stabilize the lower oxidation state . Three oxides are known : europium ( II ) oxide ( EuO ) , europium ( III ) oxide ( Eu2O3 ) , and the mixed @-@ valence oxide Eu3O4 , consisting of both Eu ( II ) and Eu... |
24.657684326171875 131 WikiText2 |
22389 Eu2O3 + 3 H2S → 2 EuS + 3 H2O + S |
93.90261840820312 12 WikiText2 |
22390 The main nitride is europium ( III ) nitride ( EuN ) . |
284.9120788574219 13 WikiText2 |
22391 = = History of study = = |
553.876220703125 7 WikiText2 |
22392 Although europium is present in most of the minerals containing the other rare elements , due to the difficulties in separating the elements it was not until the late 1800s that the element was isolated . William Crookes observed the phosphorescent spectra of the rare elements and observed spectral lines later a... |
54.52218246459961 55 WikiText2 |
22393 Europium was first found in 1890 by Paul Émile Lecoq de Boisbaudran , who obtained basic fractions from samarium @-@ gadolinium concentrates which had spectral lines not accounted for by samarium or gadolinium . However , the discovery of europium is generally credited to French chemist Eugène @-@ Anatole Demarç... |
75.47463989257812 88 WikiText2 |
22394 When the europium @-@ doped yttrium orthovanadate red phosphor was discovered in the early 1960s , and understood to be about to cause a revolution in the color television industry , there was a scramble for the limited supply of europium on hand among the monazite processors , as the typical europium content in... |
45.02177810668945 224 WikiText2 |
22395 Frank Spedding , celebrated for his development of the ion @-@ exchange technology that revolutionized the rare earth industry in the mid @-@ 1950s , once related the story of how he was lecturing on the rare earths in the 1930s when an elderly gentleman approached him with an offer of a gift of several pounds o... |
45.13789749145508 128 WikiText2 |
22396 = = Applications = = |
1041.6712646484375 5 WikiText2 |
22397 Relative to most other elements , commercial applications for europium are few and rather specialized . Almost invariably , they exploit its phosphorescence , either in the + 2 or + 3 oxidation state . |
171.86790466308594 35 WikiText2 |
22398 It is a dopant in some types of glass in lasers and other optoelectronic devices . Europium oxide ( Eu2O3 ) is widely used as a red phosphor in television sets and fluorescent lamps , and as an activator for yttrium @-@ based phosphors . Color TV screens contain between 0 @.@ 5 and 1 g of europium oxide . Wherea... |
44.39533615112305 243 WikiText2 |
22399 An application that has almost fallen out of use with the introduction of affordable superconducting magnets is the use of europium complexes , such as Eu ( fod ) 3 , as shift reagents in NMR spectroscopy . Chiral shift reagents , such as Eu ( hfc ) 3 , are still used to determine enantiomeric purity . |
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